Improvement in telescopic gun-sights



D- WOOD.

.Tel'escopic Gun Sight. I No. 42,983. Patented May 31, 1-864;

N. Ftrzns Phowu'mognphor. Wnhin ten. ac.

UNITED STATES PATENT UEETQE.

DANIEL \VOOD, OF ROCHESTER, NEW YORK.

IMPROVEMENT IN TELESCOPIC GUN-SIGHTS.

Specification forming part of Letters Patent No. 412,983, dated May 31, 1864.

- To all whom. it may concern.-

Brenoe being had to the accompanying draw- -1ngs, making a part of this specification, in which Figure 1 is a longitudinal section of the hair i I frame or tube 0 and a portion of the telescopic tube'B, with the sections or caps B and B and theeyeglass D. Fig. 2 is an endview of the hair-frame, showing the relative arrangement of the several hairs. Fig. 3 shows how a less number of hairs may be arranged.

' ,-';The nature of this invention consists in the arrangement of several horizontal cross hairs or lines in a telescope to be used in gunnery,

the spaces between the hairs increasing from the upper one downward in a ratio corresponding with the fall of the ball at different ranges,

the several hairs thereby providing fixed and accurate sights for various distances without changing the position of the telescope, and by *comparing the vertical distance between the two upper hairs with the known height or vertical length of an object at an unknown distance the gunner, having ascertained what the space measures at ten rods, for instance, is able to measure at once the distance to any object within the range of his gun, or even within the optical power of his telescope. The hairsnumbered(1234,&c.) are attached to the ordinary hair frame or tube, 0, and it is placed within the tube B of the telescope, with the hairs. next in front and at or near the focal distance of the eyeglass, as seen in Fig. 1.

, The points where the several horizontal parf allel hairs or lines cross the vertical one are .-intended to represent the fall of the ball at i ditt'erent distances, and they should be so arranged as to be in exact ratio with and to correspond thereto. The proper locality for thesecross-hairs may be determined in the foljlowing manner, viz: Arrange the upper hair, 1 No.1, about as shown in Fig. '2, then sight through it directly at the center of the target, 7 it being placed, say, at ten rods distant, when the ball will be found to have struck below the center, and by turning up the telescope (the gun remainingfix'ed with said hair sighted on the center of the target) until this hair, No. 1, ranges on the center of the ball-hole, you then have the exact sight for that distance, for by this process the line of sight and trajectile are broughttogether, which is the pointblank range; or, in case the ball of the first shot should strike above instead of below the center of the target, by reversing this process the same result is attained. Now remove the target to twenty rods and sight at the center by the same hair, No. 1, then at thirty rods, then at forty, and so on up to eighty rods, and the several successive ball-holes will indicate the proper location for the hair representing each successive distance, and, as will be seen, the figure numbering each hair will also be the initial figure of the number of rods that that hair is sighted for. This arrangement of the cross hairs or lines is for short distances; but when long ranges are required, N01 1 hair may be sighted, for instance, at eighty rods, and the relative arrangement of the other hairs ascertained, as above shown. It must be remembered that with the same gun and sight like charges of powder, ball, and patch should always be used, and also that the arrangement of the hairs here described is for a telescope in which the object appears in its natural position, and not inverted; but in using a telescope which inverts objects the order of the arrangement of the hairs, as above shown, should be reversed.

That the gunner may be able to compute the should first ascertain what the exact vertical distance between hairs Nos. 1 and 2 would measure on a target at, for instance, ten rods distant, which we will suppose to be one inch; and, if so, it would be two inches for twenty rods, three for thirty, four for forty, and in that ratio for any other distance. He may also determine at the same time the vertical measurement of the space between hairs Nos. 1,2, and 3, as seen in Fig. 3, for same distance, the measurement of either of which would be doubled at twenty rods, tripled at thirty, quadrupled at forty, and so on as before, and now, by remembering that the average vertical length of a mans head, for example, is about nine inches, and finding, as we will suppose, that it just fills the space hedistance to any object he wishes to shoot, he

tween hairs Nos. 1 and 2, We will multiply the number of inches by ten, (being the number of rods to the inch,) and the product will be the number of rods to the object, which in this case is ninety rods; but if the said upper space measures one and one-half inches at ten rods, it will be three inches at twenty, four and onehalf at thirty, and six at forty, or one and one-half inch for every ten rods of elongated distance; or, if it should measure two inches in ten rods, it would be four in twenty, &c. lhe gunner has only to make himself acquainted with the average height or vertical range of familiar objects to enable him at once to compute the distances to them,

whcreby the invention is rendered at once simple, practicable, and effective.

I claim The adjustment of several horizontal cross or projectile at the different distances for which each hair is arranged, substantially in the manner and for the purposes specified.

DANIEL WOOD.

WVitnesses:

WM. S. LOUGHBOROUGH, J. L. REQUA.

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